Alexius II Comnenus

On Manuel's death, Maria, who had been immured in a convent under the name of Xene, had herself proclaimed regent (1179-1180), and handing over her son to evil counsellors, who encouraged him in every vice, supported the government of Alexius the protosebastos (nephew of Manuel), who was popularly believed to be her lover. The young Alexius and his friends now tried to form a party against the empress mother and the protosebastos; and his sister Maria, wife of Caesar John, stirred up riots in the streets of the capital.

Their party was defeated (May 2, 1182), but Andronicus Comnenus took advantage of these disorders to aim at the crown, entered Constantinople, where he was received with almost divine honours, and overthrew the regents. His arrival was celebrated by a barbarous massacre of the Latins in Constantinople, which he made no attempt to stop. He allowed Alexius to be crowned, but forced him to consent to the death of all his friends, including his mother, his sister and the Caesar, and refused to allow him the smallest voice in public affairs.

The betrothal in 1180 of Alexius with Agnes, daughter of Louis VII of France, a child of nine, was quashed, and he was married to Irene, daughter of Andronicus. Andronicus was now formally proclaimed as co-emperor, and not long afterwards, on the pretext that divided rule was injurious to the Empire, he caused Alexius to be strangled with a bow-string (October 1183).

Initial text from 1911 encyclopedia -- Please update as needed